AI Is Now the Undisputed Champion of Computer Chess

One year ago, two of the world’s strongest and most radically different chess engines fought a pitched, 100-game battle to decide the future of computer chess.

Of these millions of moves, Stockfish picks what it sees as the very best one—with “best” defined by a complex, hand-tuned algorithm co-designed by computer scientists and chess grandmasters.

On the other side was a new program called AlphaZero (the "zero" meaning no human knowledge in the loop), a chess engine in some ways very much weaker than Stockfish—powering through just 1/100th as many moves per second as its opponent.

In 100 games, AlphaZero never lost.

The AI engine won the match (winning 28 games and drawing the rest) with dazzling sacrifices, risky moves, and a beautiful style that was completely new to the world of computer chess.

We’re breaking open two moves in just one of the games to show the aggressive style, what it does, and what humans can learn from our new chess champion?

(Stockfish’s next move is a queen leap to h2, gobbling up White’s lone soldier on the h file.) Run this position though many advanced chess engines, and most will tell you that with the sacrificed pieces, AlphaZero is now losing.

But again and again, this magician-like chess engine makes early sacrifices like these as part of an extremely long-term strategy whose benefit won’t become clear for dozens of moves into the future.